Journal of Experimental Agriculture International

Legumes, along with cereals, can be considered a main plant source of energy and quality proteins. A versatile legume crop, cowpeas offer economic, agronomic, environmental, and nutritional advantages. Cowpeas have a high total protein level and a relatively low fat content, making them nutritionally similar to other pulses. The study aimed to evaluate the effects of different rates of ammonium molybdate and Rhizobium inoculation on the yield and nutrient uptake of vegetable cowpea. There were 12 treatment combinations comprising six concentrations of molybdenum i.e. M₀:control, M₁: soil application of molybdenum @ 200 g ha^-1, M₂: soil application of molybdenum @ 300 g ha^-1, M₃: seed treatment of molybdenum 25 g ha^-1 seeds, M₄: seed treatment of molybdenum 50 g ha^-1 seeds and M₅: seed treatment of molybdenum 6 ml kg^-1 seeds and two levels of Rhizobium i.e. R₀: without Rhizobium seed treatment, R₁: with Rhizobium (10 ml kg^-1 seed) seed treatment in a Randomized Block Design (Factorial) with three replications.

Results indicated that the application of ammonium molybdate and Rhizobium inoculation significantly improved total cowpea yield. The highest yield was observed with the treatment combination of 300 g ha⁻¹ ammonium molybdate (M₂) and Rhizobium inoculation (R₁). Nutrient analysis revealed that phosphorus, potassium and iron content in cowpea pods significantly increased with ammonium molybdate and Rhizobium treatments. The highest phosphorus and potassium contents were recorded with M₂ treatment, while the maximum iron content was found in M₃ treatment. Rhizobium treated seeds (R₁) also enhanced phosphorus, potassium and iron content in the pods. In terms of nutrient uptake, the highest nitrogen and phosphorus uptake were observed with the combined M₂R₁ treatment. Similarly, the highest potassium uptake in pods and total potassium uptake were recorded with M₂R₁ treatment, respectively. The interaction between ammonium molybdate and Rhizobium inoculation showed significant effects on nitrogen, phosphorus and potassium uptake, highlighting the importance of these treatments in enhancing cowpea nutrient absorption and yield. The use of biofertilizers can be highly successful in restoring agricultural soil, and this study highlights the possibility of combining Rhizobium inoculation with ammonium molybdate treatment to maximize nutrient uptake and enhance cowpea yield in sustainable agriculture production.